Besma quercivoraria
In 3 days ~10% in a week ~20%
Besma quercivoraria, the oak besma, is a moth of the family Geometridae. The species was first described by Achille Guenée in 1857. It is found across southern Canada (from Newfoundland to British Columbia) and all of the United States except California.
Adults are sexually dimorphic. The wingspan is 27–41 mm. Adults are on wing from April to September in the south, from May to August in Ontario and from late May to July in Alberta. There are two generations per year. The larvae feed on the leaves of oak, elm, poplar, willow, Picea glauca, and mostly Betula papyrifera in southern Canada. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Great Smoky Mountains National Park | 🇺🇸 United States |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Washington | 🇺🇸 United States | |
| 2 | Boston | 🇺🇸 United States | |
| 3 | New York City | 🇺🇸 United States | |
| 4 | Chicago | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report an Oak Besma Moth sighting in Great Smoky Mountains National Park on a given day, based on 6 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 628th most-seen of the 822 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
April and May
In those months about 10% of wildlife watchers report an Oak Besma Moth in Great Smoky Mountains National Park on a given day, against under 5% in June to March, the lowest months.
Between midnight and 3 am
Across all the parks we cover, that three-hour window holds the most Oak Besma Moth sightings with a recorded time, and about half of them come between 6 am and 6 pm: it is seen both by day and at night.
Only Great Smoky Mountains National Park, in our data
Great Smoky Mountains National Park is the only park on Wallace's Line with enough records to rate Oak Besma Moth sightings: under 5% of wildlife watchers there report one on a given day.
GBIF citizen-science records
It is estimated from how often the Oak Besma Moth is recorded against all the insects logged in Great Smoky Mountains National Park (6 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
